髓核摘除术对腰椎生物力学特性影响的有限元研究

Finite element analysis into the effect of discectomy on lumbar biomechanical characteristics

目的采用三维有限元模型分析方法,探讨腰椎间盘突出症髓核摘除术对腰椎生物力学特性的影响。方法采用新型CAD方法精确建立腰椎L4～5活动节段有限元模型,构建正常模型、退变模型、髓核摘除模型和疤痕长入模型分别模拟正常椎间盘、退变椎间盘、髓核摘除后即刻和术后中长期时的椎间盘;并比较其生物力学特征。结果 (1)髓核摘除模型的刚度较退变模型减小,但较正常模型提高;(2)疤痕长入模型腰椎节段刚度大幅回升并超过退变模型(;3)髓核摘除后即刻小关节突接触力减小,而疤痕长入模型则表现为小关节突接触力增加。结论腰椎间盘髓核摘除术后即刻对腰椎稳定性和后部结构应力影响较小,而髓核摘除中长期后则可有腰椎运动节段变硬和关节突的应力增加。

Objective To investigate the effects on the lumbar biomechanical characteristics caused by the discectomy in the treatment of the lumbar intervertebral disc protrusion using three-dimensional finite element model analysis methods. Methods The new effective CAD methods were adopted to accurately create the L,5 segment＇s finite element model and simulate the normal disc, the degenerated disc, the denucleated disc immediately after operation as well as the postoperative disc in a long run; their biomechanical characteristics were also compared. Results （t）The stiffness of the denucleated model, compared with the normal one, was reduced; （2）the stiffness of lumbar segment drastically rose and even surpassed that of the degenerated one due to the fact that the scar tissue has been full into intra-disc cavity. （3）The facet contact force was decreased in discectomy model and the scar growth model was increased. Conclusion There is small impact on lumbar stability and posterior structure after discectomy immediately. The lumbar motion segment may stiffen and the stress of articular process may increase after discectomy in a long run.